1. Field of the Invention
This invention relates generally to switches, and more particularly, but not exclusively, to variable data transmission rate resolution in switches on a port-by-port basis.
2. Description of the Related Art
Networks, such as local area networks (i.e., LANs) and wide area networks (i.e., WANs, e.g., the Internet), enable a plurality of nodes to communicate with each other. Nodes can include computers, servers, storage devices, mobile devices, PDAs, wireless telephones, etc. Networks can include the nodes themselves, a connecting medium (wired, wireless and/or a combination of wired and wireless), and network switching systems such as routers, hubs and/or switches.
Conventionally, node owners pay switch operators based on the speed that the switch transmits data to and from a node. The speed (rate) of data transmission is generally increased or decreased linearly with a fixed resolution. In other words, the rate can be increased or decreased in quantized fixed amounts.
In order to indicate the rate in the switch, registers in the switch are set with values that are proportional to the rate required. For example, using a resolution of 64 Kbps, a register value of 1 would indicate 64 kbits while a register value of 2 would indicate 128 kbps. Accordingly, a 15-bit register would be required to indicate a maximum rate of 100 Mbps.
A disadvantage of the current system and method to indicate port speed is that the resolution is fixed across the full range of possible rates. Accordingly, the resolution may be too high when increasing the rate at high rates. For example, with a 64 kbit resolution a jump in speed from 100 Mbps to 110 Mbps would require incrementing the value of the registers by 164, thereby requiring a large number of registers, which increases chip cost. Alternatively, a low resolution, such as 1 Mbps, which may be preferable at high rates, would be unusable at low rates since it would not enable setting different rates below 1 Mbps. Therefore, a new system and method is needed to overcome this disadvantage.